Are you looking for high quality replacement exhaust valves for your Lotus Turbo Esprit and would like some extra performance at the same time?
Then fitting same type type of valve that is sodium filled but with the head swirl polished will promote superior gas flow.
The helical swirl pattern reduces the thickness of the boundary air layer on the back of the valve head, thus reducing surface drag as the hot gases exit the exhaust port.
With some careful valve seat work where multiple seat angles and seat under-cut are used to exploit the port, some useful additional horse-power can be realised.
These high quality valves weigh in at 52 grams
Overall length = 4.450" (113.0mm)
Head diameter = 1.215" (30.87mm)
Stem diameter = 0.313" (7.95mm)
Stem clearance in guide = 0.0006" 0.0027" (0.030mm - 0.070mm)
The valve stems are flash hard-chrome-plated to maximise service life
Lotus part number for this exhaust valve is B910E1383F
Tappet clearances (cold)
Inlet - 0.005" to 0.007" (0.13mm - 0.18mm)
Exhaust - 0.010" to 0.012" (0.25mm - 0.31mm)
Then fitting same type type of valve that is sodium filled but with the head swirl polished will promote superior gas flow.
The helical swirl pattern reduces the thickness of the boundary air layer on the back of the valve head, thus reducing surface drag as the hot gases exit the exhaust port.
With some careful valve seat work where multiple seat angles and seat under-cut are used to exploit the port, some useful additional horse-power can be realised.
These high quality valves weigh in at 52 grams
Overall length = 4.450" (113.0mm)
Head diameter = 1.215" (30.87mm)
Stem diameter = 0.313" (7.95mm)
Stem clearance in guide = 0.0006" 0.0027" (0.030mm - 0.070mm)
The valve stems are flash hard-chrome-plated to maximise service life
Lotus part number for this exhaust valve is B910E1383F
Tappet clearances (cold)
Inlet - 0.005" to 0.007" (0.13mm - 0.18mm)
Exhaust - 0.010" to 0.012" (0.25mm - 0.31mm)